Fuzzy Clustering of Vertical Two Phase Flow Regimes Based on Image Processing Technique

Author(s):  
Soheil Ghanbarzadeh ◽  
Pedram Hanafizadeh ◽  
Mohammad Hassan Saidi ◽  
Ramin Bozorgmehry B.

In order to safe design and optimize performance of industrial systems which work under two phase flow conditions, it’s often needed to categorize flow into different regimes. In present work the experiments of two phase flow were done in a large scale test facility with length of 6m and 5cm diameter. Four main flow regimes were observed in vertical air-water two phase flows at moderate superficial velocities of gas and water: Bubbly, Slug, Churn and Annular. Some image processing techniques were used to extract information from each picture. This information include number of bubbles or objects, area, perimeter, height and width of objects (second phase). Also a texture feature extraction procedure was applied to images of different regimes. Some features which were adequate for regime identification were extracted such as Contrast, Energy, Entropy and etc. To identify flow regimes a fuzzy interface was introduced using characteristic of second phase in picture. Also an Adaptive Neuro Fuzzy (ANFIS) was used to identify flow patterns using textural features of images. The experimental results show that these methods can accurately identify the flow patterns in a vertical pipe.

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Soheil Ghanbarzadeh ◽  
Pedram Hanafizadeh ◽  
Mohammad Hassan Saidi

Identification of different flow regimes in industrial systems operating under two-phase flow conditions is necessary in order to safely design and optimize their performance. In the present work, experiments on two-phase flow have been performed in a large scale test facility with the length of 6 m and diameter of 5 cm. Four main flow regimes have been observed in vertical air-water two-phase flow at moderate superficial velocities of gas and water namely: Bubbly, Slug, Churn, and Annular. An image processing technique was used to extract information from each picture. This information includes the number of bubbles or objects, area, perimeter, as well as the height and width of objects (second phase). In addition, a texture feature extraction procedure was applied to images of different regimes. Some features which were adequate for regime identification were extracted such as contrast, energy, entropy, etc. To identify flow regimes, a fuzzy interface was introduced using characteristic of second phase in picture. Furthermore, an Adaptive Neuro Fuzzy (ANFIS) was used to identify flow patterns using textural features of images. The experimental results show that these methods can accurately identify the flow patterns in a vertical pipe.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Gustavo A. Montoya ◽  
Deendarlianto ◽  
Dirk Lucas ◽  
Thomas Höhne ◽  
Christophe Vallée

The interfacial behavior during countercurrent two-phase flow of air-water and steam-water in a model of a PWR hot leg was studied quantitatively using digital image processing of a subsequent recorded video images of the experimental series obtained from the TOPFLOW facility,Helmholtz-Zentrum Dresden-Rossendorf e.V.(HZDR), Dresden, Germany. The developed image processing technique provides the transient data of water level inside the hot leg channel up to flooding condition. In this technique, the filters such as median and Gaussian were used to eliminate the drops and the bubbles from the interface and the wall of the test section. A Statistical treatment (average, standard deviation, and probability distribution function (PDF)) of the obtained water level data was carried out also to identify the flow behaviors. The obtained data are characterized by a high resolution in space and time, which makes them suitable for the development and validation of CFD-grade closure models, for example, for two-fluid model. This information is essential also for the development of mechanistic modeling on the relating phenomenon. It was clarified that the local water level at the crest of the hydraulic jump is strongly affected by the liquid properties.


Author(s):  
Dong Liu ◽  
Aritra Sur

Addition of surfactants to liquids helps to eliminate intermittent two-phase flow patterns and alleviate flow instability. These features are very desirable for two-phase microfluidic applications. However, very little information is available on two-phase flow patterns of surfactant solution in the microchannels. The present paper reports a study of adiabatic two-phase flow with surfactants in a circular microchannel of a 180-μm diameter. Air-water mixtures with trace quantities of sodium dodecyl sulfate (SDS) were used in the experiments. The maximum superficial velocities measured were 4 m/s for the liquid and 65 m/s for the gas. High-speed photographic technique was employed to visualize various two-phase flow patterns and to identify the transition boundaries between different flow regimes. The results were compared to data obtained from air-water flow without surfactants. It was found that addition of surfactants brings in significant modification to the two-phase flow regimes as well as their transition characteristics in microchannels; in particular, slug flow is effectively suppressed.


2005 ◽  
Vol 27 (1) ◽  
pp. 59-65
Author(s):  
Bui Dinh Tri

This paper will present a method to identify flow patterns (bubble & slug flow) in vertical air-water two-phase flow by void fraction measurement (using an impedance probe) at Inst. of Mechanics Hanoi.


Author(s):  
M. K. Akbar ◽  
D. A. Plummer ◽  
S. M. Ghiaasiaan

Recent experimental data dealing with gas-liquid two-phase flow regimes and their transitions in microchannels with circular and near-circular cross-sections are reviewed and compared. It is shown that, for microchannels with hydraulic diameters close to 1 mm, the available data are in good agreement. These data are used as the basis for the development of a simple Weber number-based flow regime map that divides the entire flow map into four zones: a surface tension dominated zone including bubbly and plug flow patterns; an inertia dominated zone representing the annular flow regime; a dispersed/churn flow zone; and a transition zone that consists of other intermittent flow patterns. Comparison is als o made with the limited available data representing channels with slightly larger hydraulic diameters or different cross-sectional geometries, and the effects of channel cross-sectional geometry and size are examined and discussed. The areas in need of further systematic experimental investigation are identified.


2018 ◽  
Author(s):  
Munzarin Morshed ◽  
Syed Imtiaz ◽  
Mohammad Aziz Rahman

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